glass [ imenica {N/A} ]

ETYM Old Eng. glas, gles, AS. glaes; akin to Dutch, German, Dan., and Swed. glas, Icel. glas, gler, Dan. glar; cf. AS. glaer amber, Latin glaesum. Related to Glare, Glaze.
Transparent or translucent substance that is physically neither a solid nor a liquid. Although glass is easily shattered, it is one of the strongest substances known. It is made by fusing certain types of sand (silica); this fusion occurs naturally in volcanic glass (see obsidian).
In the industrial production of common types of glass, the type of sand used, the particular chemicals added to it (for example, lead, potassium, barium), and refinements of technique determine the type of glass produced. Types of glass include: soda glass; flint glass, used in cut-crystal ware; optical glass; stained glass; heat-resistant glass; and glasses that exclude certain ranges of the light spectrum. Blown glass is either blown individually from molten glass (using a tube up to 1.5 m/4.5 ft long), as in the making of expensive crafted glass, or blown automatically into a mold—for example, in the manufacture of light bulbs and bottles; pressed glass is simply pressed into molds, for jam jars, cheap vases, and light fittings; while sheet glass, for windows, is made by putting the molten glass through rollers to form a “ribbon”, or by floating molten glass on molten tin in the “float glass” process; fiberglass is made from fine glass fibers. Metallic glass is produced by treating alloys so that they take.
On the properties of glass while retaining the malleability and conductivity characteristic of metals.
(Irregular plural: glasses).
A brittle, transparent solid, formed with silicates (such as molten sand), with irregular atomic structure.
A glass container for holding liquids while drinking; SYN. drinking glass.
Glassware collectively.
The quantity a glass will hold; SYN. glassful.

looking glass [ imenica ]

A mirror; usually a ladies' dressing mirror; SYN. glass, looking-glass.

mirror [ imenica ]

ETYM Old Eng. mirour, French miroir, Old Fren. also mireor, from (assumed) Late Lat. miratorium, from mirare to look at, Latin mirari to wonder. Related to Marvel, Miracle, Mirador.
A faithful depiction or reflection.
A polished surface that forms images by reflecting light.
Any polished surface that reflects light; often made from “silvered” glass (in practice, a mercury-alloy coating of glass). A plane (flat) mirror produces a same-size, erect “virtual” image located behind the mirror at the same distance from it as the object is in front of it. A spherical concave mirror produces a reduced, inverted real image in front or an enlarged, erect virtual image behind it (as in a shaving mirror), depending on how close the object is to the mirror. A spherical convex mirror produces a reduced, erect virtual image behind it (as in a car’s rear-view mirror).
In a plane mirror the light rays appear to come from behind the mirror but do not actually do so. The inverted real image from a spherical concave mirror is an image in which the rays of light pass through it. The focal length f of a spherical mirror is half the radius of curvature; it is related to the image distance v and object distance u by the equation 1/v + 1/u = 1/f.
Liquid mirrors using, for example mercury, are formed by rotating the liquid so that gravity and centrifugal forces shape it into a perfect parabola. They have a number of advantages over solid mirrors: they do not sag and so can theoretically be made much larger; they are cheaper, and need no polishing. In 19a small number of liquid-mirror telescopes had been built for research purposes.